Today our subject is...LOVE. It's a mysterious concept, seeming spontaneous and ethereal. When I was younger, my understanding was that falling in love and spending the rest of my life with someone special was anything but scientific. I would meet the "right" person, and voilÃ !As it turns out, many studies have explored the biology and chemistry of what happens to us when we date, and enter into a long-term relationship. While many of these studies have been replicated and well documented, others are single studies or studies with limited numbers of participants. While they certainly are fascinating, I encourage you to look at the results of these studies with a critical eye. One conventional view is that there are two major drives in love - attraction and attachment. Attraction is the love-struck phase, and it often begins with lust. Lust is primarily driven by two hormones: testosterone and estrogen. Levels of cortisol (another hormone) rise, as does the amphetamine-like neurotransmitter phenylethylamine, which can lead to heightened excitement. (Note that phenylethylamine is also conveniently found in chocolate!) Attraction may be characterized by loss of appetite and lack of sleep. Additional neurotransmitters, including serotonin, norepinephrine and dopamine play important roles. The effects of serotonin, for example, can resemble the effects of obsessive-compulsive disorder; perhaps this is why people experiencing infatuation may have difficulty focusing on anyone or anything else. You can imagine that taking antidepressants, which change the levels of these neurotransmitters, could alter the way we experience and make decisions about love. One study has found that the protein "nerve growth factor" is at significantly higher than normal levels when one first falls in love. Interestingly, these levels return to normal after time passes. Nerve growth factor is known to be critical to the development of neurons, but it's unclear what role this chemical plays in the development of human attraction. The attachment phase follows the attraction phase. Attachment is a longer lasting commitment and is the bond that keeps us together. Two hormones are thought to play a role: oxytocin and vasopressin. Oxytocin is released by a number of activities, including orgasm, childbirth and exercise. It appears to make us more trusting, and to help us overcome social fears. Vasopressin is believed to actually interfere with the delivery of excitement and pleasure neurotransmitters like norepinephrine and dopamine. Does this explain why vasopressin is associated with the later parts of a more stable, long-term relationship, rather than with the intense excitement and romance of the beginning of a relationship? One study of prairie voles, a species known for its pair bonding behavior, shows that they change from promiscuous to devoted with a change in the gene related to vasopressin. MRI's reveal more clues about the mysteries of love. They have been used to show that certain regions of the brain become more active when the subject is in love. Other research investigates what factors lead to attraction. The science of evolution suggests that we are more likely to fall in love with a partner who will ultimately be successful in advancing our genes into future generations. While the traditional view is that men look for physical attractiveness and women look for support and protection, some suggest that those relationships where partners are most similar have the best long-term success. It suggests that we are attracted to partners who resemble us, and - slightly disconcertingly - our parents. Pheromones are a chemical excreted from animals (and plants as well) that trigger responses among those of the same species. Interestingly, a woman's pheromones can change with her hormone levels. While the role of pheromones in human behavior is actively under debate, could birth control pills, which alter hormone levels, theoretically have an impact on a woman's ability to attract a partner or to fall in love? It's clear that the study of the biology and chemistry of love is still inconclusive and imprecise. I imagine that there will always be those who prefer it to remain that way! Dr. Alan Frischer is former chief of staff and former chief of medicine at Downey Regional Medical Center. Write to him in care of this newspaper at 8301 E. Florence Ave., Suite 100, Downey, CA 90240.
********** Published: Feb. 13, 2014 - Volume 12 - Issue 44